Generally, a constructional structure is exposed to various harmful environments (conditions) after being constructed, such that it may be gradually deteriorated and a structural defect may occur in the constructional structure by a specific event, which may cause a serious structural problem such as a decrease in a life expectancy designed at the beginning, unexpected damage (destruction), or the like.
In other words, as a time elapses, the deterioration of the constructional structure occurs, and a load non-specifically occurring depending on a time due to wind, an earthquake, a vehicle, and the like, is applied to the constructional structure, and behavior of the constructional structure is also changed depending on a time and a load acting on the constructional structure. In addition, the constructional structure has been complicated and multi-functionalized due to the development of a material and a construction technology and a change in a design method, or the like, a scale of the constructional structure has also become large.
However, when a state of the structure is constantly maintained, a natural frequency, a damping coefficient, a mode shape, and the like, of a target structure appearing by dynamic behavior characteristics of the structure are constantly maintained, and this structure is called an integrity structure.
The deterioration or other damage allows a change to appear in an element such as mass, rigidity, or the like, in which characteristics of the structure are reflected, and this change causes a change in a dynamic characteristic value of the integrity structure.
Therefore, an effort to continuously monitor, diagnose, maintain, and manage dynamic characteristics of the structure such as health of the structure in the medium and long view is very important. To this end, structural identification (SI) should precede at a reference point in time. Recently, a smart structure technology in which the structure itself recognizes/judges a structural state thereof and has appropriate coping capability has been demanded.
To this end, a role of a structural health monitoring (SHM) system has become important. In this regard, many studies for implementing the SHM system have been conducted. The monitoring technology as described above is a technology capable of maximizing and improving stability of a structure such as a building, a bridge, or the like, by measuring, analyzing, and diagnosing a dynamic behavior situation of the structure.
The monitoring technology as described above mainly includes a process of acquiring data from a sensor attached to the structure and a process of converting the data to analyze data for evaluating damage of the structure.
However, in designing an effective structural health monitoring (SHM) system, very many technologies are required. Particularly, a structure damage identification method and data acquiring and transmitting technologies are the most important and basic.
This system generates artificial input vibrations for vibrating the structure in the structure, and performs only health monitoring based on a condition due to many problems, or the like, caused by the artificial input vibrations.
Therefore, a measuring and controlling system capable of being operated in the case of a separate emergency in addition to the structure, collecting various structure information through multi-sensing, and perform real time measurement and coping in order to evaluate structural safety of a constructional structure with respect to non-specific external force and have crisis response capability if necessary has been urgently demanded.
Here, when a plurality of sensor positions (measuring points) provided in the structure may be selectively decreased so as to be appropriate for an object mode, both of efficiency and economic efficiency may be improved. Particularly, in health monitoring requiring real time/long term measurement, processing of measured data is very numerical value-intensive and a large number of repetition calculations are required. Therefore, it is very important to maximize quality of monitored information and minimize the number of measuring instruments.
Therefore, a structural state evaluation system for a smart structure using multi-sensing of the present invention relates to a structural state evaluation system for a smart structure using multi-sensing capable of coping with and controlling vibrations in real time by reasonably and efficiently determining positions of sensors included in a constructional structure using an optimal position determining algorithm and defining a baseline structure using a finite element (FE) model improving algorithm to measure and acquire various information on the smart structure through multi-sensing and evaluate and analyze structural safety.
Korean Patent No. 10-0587821 entitled “Automatic Measuring and Control System for Safety of Structure” has disclosed an automatic measuring and control system having a function capable of continuously measuring a safety state of a bridge or a tunnel that requires safety and needs to be continuously monitored, allowing a personal management agent such as a construction inspect company or a safety diagnosis company and a public management agent such as a government, a local government, or the like, to perform monitoring, if necessary, and controlling a measuring equipment installed in a structure positioned at a long distance from the safety diagnosis company and used to secure safety of the structure.
Europe Patent Application No. 2012-168249 entitled “A method for monitoring a structure based on measurements of a plurality of sensors” has disclosed a monitoring method for identifying a development defect of a structure using collected values measured by a plurality of sensors installed in a structure such as a building, a bridge, or the like.